*{box-sizing: border-box;margin: 0;padding: 0;}
*::before, *::after{box-sizing: border-box;}
#buttons{
    position: fixed;
    z-index: 11;
    display: flex;
    right: 0;
    top: 0;
    flex-direction: column;
    margin-top: 10px;
    margin-right: 10px;
}
#buttons > button{
    margin-bottom: 10px;
    padding: 4px 8px;
}
#demo2{
    display: none;
}
#demo{
    position: fixed;
    height: 90vh;
    top: 0;
    left: 0;
    width: 100%;
    overflow-y: auto;
}
#demo::-webkit-scrollbar{
    display: none;
}
#html{
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 100vh;
}
@media (max-width: 500px){
    #html{
        height: 70vh;
    }
    #demo{
        height: 30vh;
    }
}